The Rifle and Components of Yankee Hill Machine, Inc.
By Christopher R. Bartocci
Most of the AR-clone manufacturers in the industry are merely assemblers – they do not manufacture their own parts. The further you look into it you find that many manufacturers use the same sources for certain components. Those OEM contracts are very lucrative right now being that the AR-15/M4 is the most popular rifle in the country. One of those OEM producers as well as manufacturers of their own weapons is Yankee Hill Machine Co., Inc. (YHM) of Florence, Massachusetts. Opening their doors in 1951 as a job shop, YHM broke into the gun world in the late 1960s. Around 1998, YHM started to sell complete AR-type rifles in co-op with ZM Weapons.
As of 2014, YHM manufactures a wide array of components including rifle receivers, back-up sights, front sights, rail systems, flash suppressors, lower receiver accessories as well as sound suppressors. They also have a very good size selection of complete rifles ranging from entry level to professional. Along with their complete rifle line, they also sell complete upper receivers whether they are stock items or custom items. YHM has earned their reputation for quality and innovation. One does not have to look very far to see any of the other manufacturers using YHM parts.
One of their premier carbines, the "Smooth Carbine.” was sent for testing that features many of the YHM designed and manufactured components. Also sent for review were several of their accessories, many ones that they sell to other manufacturers as well as upgrade components.
The Smooth Carbine (YHM-8200) is a light 7 pound carbine chambered in 5.56mm caliber. YHM also offers rifles chambered in 6.8mm Rem SPC, 9x19mm and 300 Blackout. The overall length of their carbine is 32.5 inches with the telescopic stock in the closed position and 36.5 inches with the stock in the fully extended position.
The upper receiver is manufactured by YHM from 7075 T6 aircraft grade aluminum and hard coat anodized flat black. The inside of the receiver is coated with a dry film lubricant. On the left side of the receiver, it is marked 5.56mm, which is not standard on YHM-15s, but if you wish to have this caliber, or any caliber marked, they can switch out the upper receiver for the end user. The upper receiver has the standard forward assist, ejection port dust cover and fired cartridge case deflector.
The handguard is the YHM Free Floating Diamond Series handguard in the carbine length. This handguard is designed for comfort while incorporating a continuous top rail as well as three fixed 2.5 inch rail sections. However, if the user requires more mounting real estate, additional rail sections may be added with no issue. This particular model (YHM-5000) also has additional length that goes around the front sight base protecting the front sight base/sight from damage and giving an extra couple inches to the carbine rail. The rail is manufactured from 6061-T6 aluminum. The machining on the handguard was very well done and the fit and finish was impressive.
The rifle was also equipped with the YHM designed and manufactured A2-style Flip Rear Sight. This sight has both long and short range apertures as well as an adjustable windage knob (YHM-9680). These are also a very common OEM items as well as a common upgrade. YHM also offers an A1-style that requires a bullet tip or suitable tool to make adjustments (YHM-9680-A1). If the end user is not using a Front Sight Tower, YHM offers same plane removable quick deploy folding front sights. These are push button deployed and offered in a standard configuration (YHM-5030) and a hooded variation (YHM-5030-H).
The barrel on the T&E rifle was a 4140 steel, 16 inch barrel that is heat treated to RC 25-32, which is fluted for greater surface area/cooling and threaded with the standard 1/2-28 threads. This particular barrel has a 1 turn in 7 inch twist with 6 lands and grooves. The barrel extension has M4-extended feed ramps. This barrel was not melonite but YHM offers melonite barrels in 10.5, 14.5, 16 and 20 inch lengths in 5.56mm. Carbine and rifle length gas systems are offered.
The front sight base on the T&E model is a proprietary Flip Front Sight Tower designed (YHM-9394) folding front sight base. This is a very common OEM item as well as purchased as an upgrade. This front sight tower is secured by four 7/64 Allen head screws. The front sight folds down and is easily engaged. This particular model has a bayonet lug; however YHM offers a model without the bayonet lug as well. They also offer a model with a rail on the bottom of the front sight tower. YHM also offers a series of various gas blocks that are screwed on. Whatever need the operator has, YHM seem to offer a solution.
The muzzle devise on the T&E rifle is the very popular YHM designed and manufactured Phantom 5C2 (Aggressive Endcuts Comp/Flash Suppressor YHM-28-5C2). This Phantom has been redesigned to work as a muzzle compensator while maintaining the excellent flash hiding capabilities of its predecessor. The five ports have no downward facing port and is of a "no snag" design. YHM also offers the smooth end Phantom Comp/Flash Hider (YHM-28-5C1) as well as original Phantom Flash Suppressor (YHM-28A), which is known as being one of the most effective flash suppressors in the industry.
The lower receiver is manufactured from a 7075 T6 aircraft grade aluminum forging and hard coat anodized. The receiver extension is of the commercial type and allows six positions for the standard commercial sliding stock. The receiver used the Yankee Hill Machine EZ Pull takedown pins. These are extended on the right side so they are easy to pull out and allow for faster changing out of top ends. The pistol grip on the rifle was the standard Mil-Spec A2 grip. The trigger group of this rifle was the standard Mil-Spec. The lower receiver is marked multi for caliber as well.
The bolt carrier group of this rifle was of the standard configuration. The carrier group was manganese phosphate finished with a standard firing pin.
For an optic, the Trijicon ACOG was added to the rifle. This 4x20 optic is ideal for a combat rifle. The 4x magnification causes no problems with target acquisition. This optic is powered both by a fiber optic as well as a tritium lamp for low level light. The optic exterior is manufactured from 7075 T6 aircraft grade aluminum forging the same as the rifle receivers.
The rifle was fired with several different magazines to determine compatibility. These magazines included the Gen 3 Magpul PMag, Lancer AWM, Hera H3T, C-Products Defense, Troy Battle mag, H&K High Reliability magazine and the standard GI magazine. The ammunition used for testing the rifle was M855 ball ammunition as well as Hornady 75 grain TAP ammunition. There were a total of 300 rounds fired through the rifle with these various magazines. There were no malfunctions at all during the test. The target was 50 yards away. The best group obtained was approximately .60 inches and oddly enough it was with the M855 ball ammunition, which is not known for precision accuracy. The rifle was solid and well built. This was not a new rifle as this rifle had probably been sent out to several writers before it got to me. The rifle was well broken-in and worked like a Swiss watch.
Some other excellent YHM products are their sling mounts. They offer ambidextrous mounts that are part of the receiver extension end plate. The most popular model is the ambidextrous single point sling mount (YHM-9757). This is a very popular OEM product as well as an upgrade to any rifle. They also offer right hand model for the carbine (YHM-9756) as well as for the standard rifle stock (YHM-9755). The slotted ambidextrous mode (YHM-9758) is similar but with the addition of a 1" sling slot on each side. To install, simply remove the stock assembly and replace the YHM receiver extension plate with the standard factory one.
The Lo-Pro gas block (YHM-9384) is one of YHM's biggest OEM products. This gas block is attached via two clamp screws. Another model (YHM-9383) is offered using set screws to attach. The low profile gas block allows slide over handguards to be installed without removal of the gas block as well as allowing extra-long handguards to be installed that cover the gas block.
YHM offers an excellent forward grip offered in three models. The first is the Quick Action (YHM-9640), which is the one sent with the T&E rifle. Deployed by a button, the grip swings either forward or backward depending on how it is mounted. To make the grip even better, a Manta vertical grip sleeve was added. When the grip was swung up in the stowed position, it could also be used as a grip to hold the rifle. The Folding model (YHM-9560) swings either forward or backward by depressing the button. It has three instead of two positions. The third model is the Fixed version (YHM-9400), which does not move at all.
Also sent for evaluation was one of their new rails; the SLR Forearm (Slim-Light-Rail). The particular model was the Rifle Length Smooth model (YHM-5160). This handguard is 5/8 of an inch thinner than the standard YHM handguard. This model offered a continuous top rail. The rest of the rail is fully customizable to the shooter. Rail segments are offered in 3, 4, 6, 8 and 12 inches in length as well as a 1/4 or 3/8 inch height. The rail and rail segments are manufactured of 6061-T6 aluminum. Mounting of this rail is quite simple. The front sight base of the barrel and flash hider is removed and the existing barrel nut removed. The YHM barrel nut is installed in its place and tightened with a provided wrench. There is no aligning of the gas tube necessary. The rail attached to the YHM barrel nut and is secured by five screws.
These are but a few of the products offered and manufactured by Yankee Hill Machine. There is no doubt this company manufactures top tier firearms and accessories. These products are offered by many OEM's as well as Brownells. Barrels, handguards, sights, gas blocks, angled rail mounts, scope mounts, scope rings, vertical pistol grips, enhanced takedown pins, muzzle devices, complete rifles and sound suppressors. They’ve got it all.
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